My 2nd attempt at making a balance staff

[caseback]

A little over a week ago I tried making something resembling a balance staff for the first time. It wasn't for any specific watch, just trying to get a feel for how the gravers and steel "worked".

I got encouraging feedback , so today I decided to try again. Now for an actual project, a Junghans J47 with both balance staff pivots broken. I do actually have some new balance staffs for this specific movement, so that made it easier to get good measurements.

I won't ask you to spot the differences between the DCN staff and mine (my wife sometimes says I'm snotty enough already), but any feedback is greatly appreciated..

Tonight I'll fit the wheel, finish the pivots on the jacot tool and see if it will actually work..

Edited September 26, 2024 by caseback
Typos

[nickelsilver]

I think it's the upper one? Looks fantastic, good job!

[caseback]

3 minutes ago, nickelsilver said:

I think it's the upper one? Looks fantastic, good job!

Thank you .

Yes. The finish on DCN staff is a bit rough. 

You can tell that on mine I have to trim the pivots from 0.125mm to 0.11mm and round the tips on the jacot tool.

[praezis]

6 minutes ago, caseback said:

and round the tips on the jacot tool

… but not too much, just slightly, after having them ground flat with the Arkansas first.

[oldhippy]

Excellent work and this is only your second time. You sure have the knack for this type of thing. I would say you made the first in the picture. 

[nickelsilver]

Seriously, we sometimes have a watchmaker make a staff as part of their bench test. Most, who were recent multi-year watch school grads, failed. These are folks who spent months doing supervised turning. What you've done is super impressive.

[Nucejoe]

 Impressed,

You were born a staff turner.

Second one gets my vote as pivot end looks not rounded to my weak eyesight.

[caseback]

14 minutes ago, Nucejoe said:

 Impressed,

You were born a staff turner.

Second one gets my vote as pivot end looks not rounded to my weak eyesight.

Thank you. Mine is the first one though. The DCN brand staff is a bit rough. Mine's shiny . Could very well be that the rougher surface of the production staff is intentional, to get an easier friction fit perhaps?

[RichardHarris123]

I agree with all the comments, you have done a superb job but I have a couple of questions.  Is there a notch out of the top one and is the bottom one under cut, for want of a better word?  As highlighted in the attached. 

Please note, I haven't turned anything so this is a genuine question and not criticism in any form  

[caseback]

Hi Richard. Any comments are welcome.

I have looked at them again, but can't see any notches or undercuts. Might be some rodico residue? I do need to dress the pivots on the jocot lathe. I stopped turning them when they were 0.125mm. 

 

[RichardHarris123]

I can't see them on your new photos either, so either the light or left over Rodico. 

Again, nothing but respect from me. 

[nevenbekriev]

My respect, the staff looks professional. If the material is good and the hardness is correct, then You have made perfect balance staff. Of course, reducing the pivots diam on the Jakot toll is something that needs to be done, and this is another job that is tricky for one who will do it for first time. Nothing frightful when some experience is gained, but usually a newbie will break some pivots in the beginning and this is normal thing. Will say here that I personally prefer not to use Jakot tool, but do the burnishing on the lathe right after the pivot has been turned. This method is not safer, and some experience is needed too.

[caseback]

Testfitting on the plate after burnishing the pivots on the jacot lathe. 

Edited September 27, 2024 by caseback

[nickelsilver]

Nice! When I make a staff (just did another this morning) my "test" is does the balance stay still (no hairspring) when gently twisting the movement holder on the bench. Like ice in a glass of tea. It's not scientific but after all these years I can tell by how it behaves if it needs a few microns off the diameter or something.

[caseback]

4 minutes ago, nickelsilver said:

Nice! When I make a staff (just did another this morning) my "test" is does the balance stay still (no hairspring) when gently twisting the movement holder on the bench. Like ice in a glass of tea. It's not scientific but after all these years I can tell by how it behaves if it needs a few microns off the diameter or something.

Ah! Just letting inertia doing it's thing. Good one! thnx!

[caseback]

My plan for tonight was to assemble the balance complete and get it on the main plate with the pallet fork to check if that fit was ok as well. When I fitted the pallet fork, I noticed a lot(!) of play. Turned out the staff is loose.. Someone has put a hammer on it by the looks of it. 

So, apart from the brokenbalance staff, the bent balance cock, the bent extended pivot for the sub seconds hand and the missing tooth on the rachet wheel, I also have to fix the pallet fork (and apply some fresh shellac). Nice project.  

At least I got the balance spinning nicely.

Added: I removed the pallet fork staff. This is turning out to be a project with a lot of new challenges for me. I'll probably have to make a new staff for the pallet fork as well.

 

Edited September 27, 2024 by caseback
Typo's, added extra picture

[Klassiker]

You can make a better staff than that one with your eyes closed!

[caseback]

It actally looks like it used to have threads. No sign of those in the fork itself..

[nevenbekriev]

Actually You have more problems with the pallet fork. The entrance pallet is wrong - it is actually an exit one. The slope of the impulse plain is much bigger than it should be. Then the staff - Yes, it is threaded, but I don't remember how it should be on this Junghans. Seems like somebody modified the staff to fit here, the pivots look as shaped by almost blind watchmaker. Anyway, You can make new staff and there is no need it to be threaded, but have in mind that the fork can be deformed due the experiments of the previous master so the angles and distance between stones tips may need correction by deforming of the body of the fork. And the entrance pallet must be replaced, or reshaped at least.

[caseback]

Thnx Nev!

Yes, to use an understatement: it sure has some issues . I hadn't noticed the incorrect stone, but what I did see was that it's already bent, the hole for the staff is deformed and there are very crude file-marks. I might be better off sourcing a replacement, but I'm tempted to try and nurse this one back to some "health". I'll give it some thought..

What's also troubling, is that there is now way of knowing what part (if any) of the pallet fork is even meant for this movement. Copying the staff and getting it to fit the fork would be easy, but I'll have to take some measurements first to check if the hight is correct.

 

Edited September 28, 2024 by caseback

[Klassiker]

21 minutes ago, caseback said:

I might be better off sourcing a replacement

That's what I'd try to do, but I'm lazy and they are not easy to find. Top marks to you for perseverance.

[tomh207]

I’m now eagerly awaiting the “I made my first pallet fork” post

well done on your achievements @caseback

 

Tom

[nevenbekriev]

5 hours ago, caseback said:

What's also troubling, is that there is now way of knowing what part (if any) of the pallet fork is even meant for this movement.

I would use the existing staff to determine is this fork able to work correctly with this movement. This means the rear part to work well with the balance roller and the front part with the escape wheel. If You need guidance, I will explain everything that needs to be checked, but it will need some writing. Actually, the pallet fork is complicated part that have to comply with many things in the movement

[caseback]

3 minutes ago, nevenbekriev said:

I would use the existing staff to determine is this fork able to work correctly with this movement. This means the rear part to work well with the balance roller and the front part with the escape wheel. If You need guidance, I will explain everything that needs to be checked, but it will need some writing. Actually, the pallet fork is complicated part that have to comply with many things in the movement

Thank you for your kind offer. Very much appreciated!

I'll make a replacement staff, put it together and see what it does. I'm sure I'll have some questions to ask you by then.

[caseback]

Well, I've made and fitted a new pallet fork staff, replaced the pallet jewels and straightened the seconds hand pivot. The pallet fork locks and unlocks the escapewheel so I'm itching to see if she'll actually run, but there's another thing that needs fixing first. The ratched wheel is missing a tooth. Yes I know it will still work without it, but what's the fun in that..? Can anyone tell me what the recommended method for this is? Making a slot with a small saw, solder in a new piece and file it in shape? If so, brass or steel? 

Edited October 15, 2024 by caseback